Kennedy thanks the staff of the Department of Earth Sciences, Oxford, and the University Museum of Natural History, Oxford, for technical support. The financial assistance of the Strakosh Bequest and the Oppenheimer Fund (Oxford) is acknowledged. Lorna Steel (The Natural History Museum, London) provided access to specimens in her care. Klinger acknowledges the financial aid of the NRF (South Africa) and technical staff of the Natural History Collections Department, Iziko South African Museum. The originals of Figs 1-6, 30, 31 were supplied by the photographic unit of the Natural History Museum, London.